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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_icl.implementation"></a><a class="link" href="implementation.html" title="Implementation">Implementation</a>
</h2></div></div></div>
<div class="toc"><dl class="toc">
<dt><span class="section"><a href="implementation.html#boost_icl.implementation.iterative_size">Iterative size</a></span></dt>
<dt><span class="section"><a href="implementation/complexity.html">Complexity</a></span></dt>
<dt><span class="section"><a href="implementation/inplace_and_infix_operators.html">Inplace
      and infix operators</a></span></dt>
</dl></div>
<p>
      The <a class="link" href="interface.html" title="Interface">previous section</a> gave an overview
      over the interface of the <span class="bold"><strong>icl</strong></span> outlining <a class="link" href="interface.html#boost_icl.interface.class_templates" title="Class templates">class templates</a>, <a class="link" href="interface/associated_types.html" title="Associated Types">associated types</a> and
      polymorphic <a class="link" href="interface/function_synopsis.html" title="Function Synopsis">functions
      and operators</a>. In preparation to the <a class="link" href="function_reference.html" title="Function Reference">next
      section</a>, that describes the <span class="bold"><strong>icl's</strong></span> polymorphic
      functions in more detail together with <span class="emphasis"><em><span class="bold"><strong>complexity
      characteristics</strong></span></em></span>, this section summarizes some general
      information on implementation and performance.
    </p>
<h6>
<a name="boost_icl.implementation.h0"></a>
      <span class="phrase"><a name="boost_icl.implementation.stl_based_implementation"></a></span><a class="link" href="implementation.html#boost_icl.implementation.stl_based_implementation">STL
      based implementation</a>
    </h6>
<p>
      The <span class="bold"><strong>implementation</strong></span> of the <span class="bold"><strong>icl's</strong></span>
      containers is based on <span class="bold"><strong>std::set</strong></span> and <span class="bold"><strong>std::map</strong></span>. So the underlying data structure of interval
      containers is a red black tree of intervals or interval value pairs. The element
      containers <a href="http://www.cplusplus.com/reference/stl/set/" target="_top"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span></code>
      </a> and <code class="computeroutput"><a class="link" href="../boost/icl/map.html" title="Class template map">icl::map</a></code> are wrapper
      classes of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span></code> and <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span></code>. Interval
      containers are then using <a href="http://www.cplusplus.com/reference/stl/set/" target="_top"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">sets</span></code></a>
      of intervals or <code class="computeroutput"><a class="link" href="../boost/icl/map.html" title="Class template map">icl::maps</a></code> of interval
      value pairs as implementing containers. So all the <span class="emphasis"><em><span class="bold"><strong>complexity
      characteristics</strong></span></em></span> of icl containers are based on and limited
      by the <span class="emphasis"><em><span class="bold"><strong>red-black tree implementation</strong></span></em></span>
      of the underlying std::AssociativeContainers.
    </p>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="boost_icl.implementation.iterative_size"></a><a class="link" href="implementation.html#boost_icl.implementation.iterative_size" title="Iterative size">Iterative size</a>
</h3></div></div></div>
<p>
        Throughout the documentation on complexity, big <span class="emphasis"><em>O</em></span> expressions
        like <span class="emphasis"><em>O(n)</em></span> or <span class="emphasis"><em>O(m log n)</em></span> refer to
        container sizes <span class="emphasis"><em>n</em></span> and <span class="emphasis"><em>m</em></span>. In this
        documentation these sizes <span class="emphasis"><em><span class="bold"><strong>do not</strong></span></em></span>
        denote to the familiar <code class="computeroutput"><span class="identifier">size</span></code>
        function that returns the <span class="emphasis"><em><span class="bold"><strong>number of elements</strong></span></em></span>
        of a container. Because for an interval container
</p>
<pre class="programlisting"><span class="identifier">interval_set</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">mono</span><span class="special">;</span>
<span class="identifier">mono</span> <span class="special">+=</span> <span class="identifier">interval</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;::</span><span class="identifier">closed</span><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="number">5</span><span class="special">);</span> <span class="comment">// {[1 ... 5]}</span>
<span class="identifier">mono</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span>           <span class="special">==</span> <span class="number">5</span><span class="special">;</span>         <span class="comment">// true, 5 elements</span>
<span class="identifier">mono</span><span class="special">.</span><span class="identifier">interval_count</span><span class="special">()</span> <span class="special">==</span> <span class="number">1</span><span class="special">;</span>         <span class="comment">// true, only one interval</span>
</pre>
<p>
      </p>
<p>
        it's size and the number of contained intervals is usually different. To
        refer uniformly to a <span class="emphasis"><em>size</em></span> that matters for iteration,
        which is the decisive kind of size concerning algorithmic behavior there
        is a function
</p>
<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">T</span><span class="special">::</span><span class="identifier">iterative_size</span><span class="special">()</span><span class="keyword">const</span><span class="special">;</span> <span class="comment">// Number of entities that can be iterated over.</span>
</pre>
<p>
        for all element and interval containers of the icl. So for complexity statements
        throughout the icl's documentation the sizes will be <code class="computeroutput"><span class="identifier">iterative_sizes</span></code>
        and big <span class="emphasis"><em>O</em></span> expressions like <span class="emphasis"><em>O(m log n)</em></span>
        will refer to sizes
</p>
<pre class="programlisting"><span class="identifier">n</span> <span class="special">=</span> <span class="identifier">y</span><span class="special">.</span><span class="identifier">iterative_size</span><span class="special">();</span>
<span class="identifier">m</span> <span class="special">=</span> <span class="identifier">x</span><span class="special">.</span><span class="identifier">iterative_size</span><span class="special">();</span>
</pre>
<p>
        for containers <code class="computeroutput"><span class="identifier">y</span></code> and <code class="computeroutput"><span class="identifier">x</span></code>. Note that
</p>
<pre class="programlisting"><span class="identifier">iterative_size</span></pre>
<p>
        refers to the primary entities, that we can iterate over. For interval containers
        these are intervals or segments.
</p>
<pre class="programlisting"><span class="identifier">Itervative_size</span></pre>
<p>
        never refers to element iteration for interval containers.
      </p>
</div>
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<td align="right"><div class="copyright-footer">Copyright © 2007-2010 Joachim
      Faulhaber<br>Copyright © 1999-2006 Cortex Software
      GmbH<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
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